NAT scopes take 2 --> PR #50

[garethsb]

Proposal based on Zoom call 10-Feb-2020 and subsequent feedback, to add the three levels of scope to PR #50 in a different way.

[garethsb]

This PR allows:

• GET /network-address-translations (for all NAT policies)

• GET /network-address-translations?translation_scope.level=root (for'global' NAT policies)

• GET /network-address-translations?translation_scope.level=network_device&translation_scope.device_id={networkDeviceId} (for NAT policies only applied at the switch level on the specific switch)

• GET /network-address-translations?translation_scope.level=network_device_interface&translation_scope.device_id={networkDeviceId}&translation_scope.port_id=Ethernet%201/2 (for NAT policies only applied on the specific interface)

It also allows some other queries which may or may not be useful:

• GET /network-address-translations?translation_scope.level=network_device (for NAT policies only applied at the switch level on any switch)
• GET /network-address-translations?device_id={networkDeviceId} (for NAT policies only applied at the switch or interface level on the specific switch)

[garethsb]

Approved by @vsachin33 by email.